PolyVISIONS Inc. is a specialty plastics company situated close to York, Pennsylvania, which has a broad range of extrusion and mixing capabilities. As the company processes more than 25 generic resin products with a wide range of custom additives, they need a heat transfer fluid with dependable thermal stability and lowest impact from oxidation. Eight years ago they chose Paratherm NF® and they still continue to use this non-fouling, non-toxic heat transfer fluid.
The present manufacturing facility in Manchester, Pennsylvania, was started in 1996. There are 13 employees and the company produces annual revenues of $2 million from its production of over one million pounds of polyolefin and polyester compounds. These specialty additive compounds are delivered to a broad range of manufacturers of end use compounds which improve production processability and product properties.
Specialty Additives
Specialty additives are provided in pellet concentrate form. The outstanding performance of these specialty pellets stems from the intimate, rigorous mixing of ingredients. The company is able to combine additives uniformly into plastic raw materials, as well as develop additives that have many applications. PolyVISIONS will also change compounds from a light powder form into pellets, or process compounds that possess light powder ingredients so as to help control dust issues in customer production units.
Among the additives that PolyVISIONS uses are nucleating agents (which accelerate crystallization of plastic compounds), pigments, lubricants, surface modifiers that improve appearance, and impact modifiers that enhance the durability of plastic compounds. PolyVISIONS’s capital inventory includes a range of temperature control equipment manufactured by Advantage, Delta T, TUC and other companies circulate Paratherm heat transfer fluids are used in every PolyVISION unit to maintain precise temperatures.
Among these processing machines is a Readco Continuous Processor, initially built for food processing but adapted for PolyVISIONS’s plastic compounds. PolyVISIONS President and CEO, Larry Bourland said that the mixer’s large throat opening, large diameter barrels and deep flighted screw elements are particularly useful in combining compounds that include light, powdery ingredients.
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Readco Continuous Processor Barrel Extruder equipped with Three Roll Sheet Stack. Temperature controlled with Paratherm heat transfer fluid.
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Larry Bourland, CEO of PolyVISIONS Inc. inspects quality of extruded profile.
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Intimate mixing of polymers by Readco Extruder equipped with vertical sheet die.
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Larry Bourland demonstrates PolyVISIONS finished specialty additive products in pellet form.
Traditional extruders are designed for high-density materials, such as pellets. The Readco can handle fluffy, low bulk density materials that can be a problem for other extruders.
Larry Bourland, CEO, PolyVISIONS Inc.
Bourland first came across the intermeshing, co-rotating twin screw equipment at a Penn State University conference in 1990. Even though it was designed to blend food formulations such as candy and pasta, he recognized the equipment was suitable for mixing the powdery ingredients that PolyVISIONS uses in its compounds.
PolyVISIONS modified the unit by reconfiguring parts, such as internal elements, segmented screws and the drive train. The oddly deep flights of the Readco screw elements have large internal volumes that can house shredded materials from recycled sources more effectively.
“Feeding these non-traditional feedstocks, mixing in the molten state, and then converting the materials into traditional solid pellets is simply not a problem,” Bourland said. In fact, he was in recent times called in to help another company modify a similar piece of equipment to convert recycled telephone books into kitty litter.
The Readco Continuous Processor (or CP) is provided with a closed-loop thermal fluid system that circulates Paratherm NF which keeps the extruder barrel at a pre-set temperature. Bourland explains that over the years the Paratherm fluid has established itself as durable, reliable and hazard free.
In addition the Paratherm fluid resists oxidation better than competitive fluids so there is a lot less accumulated carbon residue in the equipment. If that residue is permitted to accumulate on the surface of heating elements, heat control becomes crippled. The same thing will happen if residue coats the pumps or the surfaces of the cooling apparatus.
Larry Bourland, CEO, PolyVISIONS Inc.
Paratherm NF
PolyVISIONS uses Paratherm NF for temperature regulation of applications of up to 550 ºF. For even higher temperature applications, heating is regulated electrically with metallic bands as heating elements. However, with this direct heating technique, a potentially dangerous situation crops up if an electrical arc comes anywhere close to the airborne powdery substances.
With Paratherm NF, of course, the heated fluid is externally circulated to the equipment eliminating the risk of electrical arcs. Paratherm also offers a more uniform distribution of heat than electrical systems. “Removing excess heat from thermal oil is also is never a problem. The temperature control units are equipped with heat exchangers that efficiently remove excess heat generated during melt processing,” Bourland adds.
Besides using in the Readco CP, PolyVISIONS controls the temperature of other mixing equipment by closed loop circulation of Paratherm NF heat transfer fluid. The other types of blending equipment include jacketed ribbon blenders, which are capable of mixing materials in the solid state. In this article, thermal fluid is circulated from the control mechanism to the blender at temperatures up to 350 ºF.
The precise even temperature provided by the Paratherm NF stimulates uniform integration of all mix components more effectively. “These tend to be long production runs,” Bourland said, “so the thermal oil can become exposed to air. If the thermal fluid we used were vulnerable to oxidation it would quickly discolor and thicken. Sooner of later this would compromise thermal performance.”
Paratherm is good but that doesn’t mean we can skip routine maintenance. If you don’t perform routine maintenance, it doesn’t matter whose products you use. Eventually, your production will come to a halt.
Larry Bourland, CEO, PolyVISIONS Inc.
This information has been sourced, reviewed and adapted from materials provided by Paratherm.
For more information on this source, please visit Paratherm.